Student Center | Instructor Center | Information Center | Home

Statistics for the Behavioral Sciences, 4/e

Michael Thorne, Mississippi State University -- Mississippi State
Martin Giesen, Mississippi State University -- Mississippi State

Graphing Data

Problems

You have gathered some test score data from a 50-item test in an introductory psychology class. In order to "curve" the grades, you decide to graph the data. The frequency distribution is shown here.
X f
48 1
47 1
46 2
42 2
41 3
39 2
38 5
37 4
36 3
35 2
33 2
32 1
30 1
N = 29
1. Construct a frequency polygon.
2. Make a histogram.
3. Construct a cumulative frequency curve.
4. Construct a cumulative percentage curve and use it to find the approximate percentage of scores at or below a score of 35.
Before using behavior modification to reduce smoking, a confirmed smoker records the number of cigarettes smoked per day over a 2-week period. Use the appropriate graph to illustrate the data.
Day f Day f

1 23 8 25
2 27 9 22
3 18 10 24
4 19 11 29
5 25 12 25
6 26 13 19
7 33 14 22
The highway patrol of an unnamed state keeps track on the number of people their officers stop for traffic violations who are wearing seat belts. They notice an apparent difference between weekdays and weekends in the proportion of people wearing seat belts. In a typical month, the number of people wearing seat belts out of the total number stopped is as follows: weekdays, 7,849 out of 11,542; weekends, 1,663 out of 3,192. Use the appropriate graph to show the results. Note that the sample sizes are different, so you will need to do something to put the groups on an equal footing.
The Registrar's Office of a small college records the number and type of requests for information it receives at its Information Desk. The numbers for a typical week are as follows: transfer of credit, 7; transcripts, 22; class availability/scheduling, 90; prerequisites, 12; other, 45. Illustrate these data with a bar graph.
The mean quality point average (QPA) has been determined by the semester after joining for the members of a campus social organization. Plot the result.
Semesters After Joining Mean GPA
1 2.97
2 2.65
3 2.58
4 2.45
5 2.30
6 2.19
In a recent study, patients suffering from depression received one of three types of treatment: counseling alone, antidepressant medication alone, or a combination of counseling and medication. Their average level of depression (rounded to the nearest whole number) is assessed each month for 6 months. The data are given here. Plot the three groups on the same graph for comparison.
Month Counseling Medication Counseling and Medication
1 17 16 18
2 15 10 12
3 14 9 11
4 13 11 9
5 10 10 6
6 8 9 4
Compare frequency distributions A and B on the same set of axes.
Distribution A Distribution B
X f X f

25 1 25 6
24 3 24 7
23 3 23 8
22 4 22 10
21 5 21 7
20 6 20 4
19 8 19 3
18 7 18 2
17 7 17 2
16 6 16 1
1. Construct frequency polygons. The shape of Distribution A is _________________ skewed; the shape of Distribution B is _________________ skewed.
2. Plot the distributions as cumulative frequency curves.
The following numbers are first-lap speeds in miles per hour of 35 cars in the Indianapolis 500 race. Make a stem-and-leaf plot of the speeds. Then rotate the plot 90° counterclockwise so that it looks like a frequency histogram.
183 177 159 172 210
166 167 199 185 188
203 207 197 188 193
168 175 192 201 204
169 177 185 188 189
199 193 195 205 195
188 185 192 199 198

Click here to view the answers (177.0K)

2003 McGraw-Hill Higher Education
Any use is subject to the Terms of Use and Privacy Notice.
McGraw-Hill Higher Education is one of the many fine businesses of The McGraw-Hill Companies.